| Show firefly's Firefly Still Remains Re ains Mystery Once it t was thought that phosphorus was the cause of the lumi- lumi luminosity horus of the firefly and its larva the worm glow and the phenomenon was called phosphorescence n non But the substance of the luminous zones ones of these curious beetles b has many anY tunes been exhaustively ana ana- analyzed for phosphorus p rus without an in indication in- in indication indication of its being found and the thereal thereal real nature of of- the firefly's glow re re- remains remains remains mains a secret The key to the solution seems tolie to tolie lie he in the fact that certain fats oils and other substances exhibit lumi lumi- luminosity luminoSity when permitted to combine f with oxygen in an alkaline solution I just what takes place here is not jet het known but it is a form of com com- bustion In the laboratory experiments experiments experiments ments the contact also produces a measurable amot amol amount t of heat while In the firefly and in luminous fishes h hand and plants I it t does des not appear to do doThe so I The producing light organs of the I f firefly are unquestionably arranged bring to-bring about this union umon of oxygen and a fatty secretion The seat of the light is intensely luminous areas in the abdomen or thorax or loth h. h Each is a specialized portion of the fat body a plate situated directly beneath the skin and sup supplied plied with nerves and fine tubes f r f connecting with the trachea or windpipe The cells of these fatty places se se- secrete secrete secrete crete under the control of the nerv nerv- nervous nervous ous system a substance which is burned during the appearance of light This combustion takes place by means of the oxygen o conveyed to o the cells by the fine tracheal branches The lighting system seems to serve two purposes One to attract the opposite sex and the other as asa a curious means of defense against bats or other nocturnal insectivorous ous creatures which prefer less daz daz- dazzling dazzling and alarming fare This de de- defensive defensive use of light has its counter counter- counterpart counterpart part in some of the luminous fish which light up only under the stimulus lous lus of alarm and excitement to frighten off ofT their enemies |
